It seems Thunderbird has a bug which prevents the correct process of the account's configuration. So, try manual configuration with no encryption, then as soon as Thunderbird accepts it you can retry the registration of the account with the encryption method.

Yes, we provide a MX backup included in all offers. In case the main mail server is not reachable it accepts your email, store it, and when the mail server comes back online it will deliver your email to it.

Trial mailboxes are usable for one month and one week. Before the expiration we will send you an email which inform you about it. After the expiration date you will have one more week for using the trial emailbox after that your trial emalbox and its content will be removed.

Servermx.com trial offer gives you the ability to try all implemented features such as domain validation, email creation and modification; furthermore you can try the mailbox reserved area. You can also use this account for purchasing paid products.